It is known that plastic films readily get electrified, which eventually limits their applications. In the photographic industry, polyethylene terephthalate films are commonly employed as the supports of silver halide light-sensitive materials. However, polyethylene terephthalate films tend to be electrified at a low humidity condition such as the wintertime. Electrification of plastic supports poses serious problems especially in the case of high-speed application of a high-speed emulsion or exposure and processing of a highly sensitive light-sensitive material by means of an automatic printer. Anti-static treatment is, therefore, a matter of crucial importance in the industry.
When a light-sensitive material is electrostatically charged, static marks tend to be formed on its surface due to electrical discharge, and foreign matters such as dust are likely to stick to its surface, allowing pinholes to be formed. Removal of such static marks and pinholes is very difficult and time-consuming. For enhanced productivity, it is of crucial importance not to allow static marks and pinholes to be formed, and for this purpose, an anti-static agent is generally employed in a light-sensitive material. Examples of anti-static agents that have recently been employed include fluorine-containing surfactants, cation surfactants, amphoteric surfactants, polyethylene oxide group-containing surfactants, polyethylene oxide group-containing polymers, and polymers containing a sulfonic group or a phosphoric group in each molecule. Generally, a layer containing such anti-static agent is provided on the back coating side of a light-sensitive material.
Some of newly developed cameras for printing and photoengraving (e.g., C-880 manufactured by Dainippon Screen Co., Ltd.) are so designed that electrostatic charges are allowed to be adsorbed onto the back coating layer of a film, then the film is wound around the drum of the camera, followed by exposure to light. In the case of such camera, provision of an anti-static layer on the back coating side of a film may result in insufficient winding of the film (jamming).